Health and Performance Outcomes from a Randomized Clinical Trial of Post-Metaphylactic Intervals Following Tildipirosin Metaphylaxis for Control of Naturally Occurring BRD in Commingled Lightweight Yearling Steers in a Commercial Feedlot

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-AABP Executive Director Dr. Fred Gingrich is joined by Dr. Josh Szasz, a veterinarian with Five Rivers Cattle Feeding. Szasz is the lead author on the paper published in The Bovine Practitioner Volume 56 Number 2 titled “Health and performance outcomes from a randomized clinical trial of post-metaphylactic intervals following tildipirosin metaphylaxis for control of naturally occurring BRD in commingled lightweight yearling steers in a commercial feedlot”. Bovine respiratory disease (BRD) remains a significant challenge in feeder cattle and is a multi-factorial disease which has components that are difficult or outside of our control. He also discusses how it is difficult to predict which cattle will experience BRD after arrival to the feedyard. This study involved 8,000 sale barn-sourced steers with an average weight of 650 pounds and the objectives of the study were to evaluate the health and performance outcomes of an extended post-metaphylactic interval (PMI) using tildipirosin. The PMI periods measured were 4, 7, 10 and 13 days. Szasz walks us through the study including case definitions, processing protocols and treatment protocols for the cattle evaluated. The results of this study indicated that BRD first pulls and morbidity decrease linearly with increased PMI. There were no negative health impacts of extending the PMI after tildipirosin metaphylaxis. Szasz also mentions that cattle pulled for treatment showed an increased body weight even during the MPI time indicating that these cattle were still eating and gaining weight during the no-treatment times even if showing signs of illness. He mentions that good animal husbandry to allow cattle to acclimate to their new surroundings is a very important component of animal care and not just antimicrobial treatment. This study demonstrates that veterinarians should review protocols with clients to discuss the appropriate PMI for cattle to not only improve animal care but also implement good stewardship principles for judicious antimicrobial use.

Szasz JI, Bryant TC, Bryant LK, Streeter MN, Hutcheson JP, & Renter DG (2022). Health and performance outcomes from a randomized clinical trial of post-metaphylactic intervals following tildipirosin metaphylaxis for control of naturally occurring BRD in commingled lightweight yearling steers in a commercial feedlot. The Bovine Practitioner, 56(2), 38–46. https://doi.org/10.21423/bovine-vol56no2p38-46